1. Field of the Invention
The invention concerns a transverse flux machine with conductor rings that are enclosed on three sides by U-shaped soft magnetic bodies.
2. Description of Prior Art
The rotor of known permanently excited transverse flux machines consists of a multitude of hard and soft magnetic segments which entails costly prefabrication and assembly. Production costs are increased by the intricate structure, particularly, if in spite of the high magnetic forces a design that is free of vibrations is to be achieved.
In DE 37 05 089 A1, the soft magnetic elements W together with the permanent magnets Md form two rows. Additional permanent magnets Mq are arranged between the soft magnetic elements of the two rows. The block-shaped concentrator segments and the permanent magnets which are arranged checkerboard-style lie between the ends of different U-shaped pole elements. If the soft magnetic elements move in relation to the pole elements, said soft magnetic elements are subjected to a force that is pulling them alternately toward the pole elements on the different sides. These pulsating forces which are offset by 180.degree. at the two sides cause the structure to vibrate and result in considerable stability problems.
In DE 41 38 014 C1 also, permanent magnets are arranged between soft magnetic elements in a ring. The ring consists in direction of the circumference only of slantwise arranged permanent magnets and concentrator segments which are alternating. Said ring is completely disposed between the ends of U-shaped pole elements of a conductor ring. Pulsating forces act in radial direction on the soft magnetic elements. These forces are offset on the inside versus the outside in time by 180.degree.. The excitation causes the ring to vibrate and said ring is therefore not firmly anchored to the rotor.
U.S. Pat. No. 4,658,166 and U.S. Pat. No. 4,682,067 show a synchronous electric motor comprising an axially magnetized rotor disc with opposite flat faces. In circumferential direction an end of a U-shaped member is arranged opposite of only every other magnetic pole. Of the magnetic material used in the construction less than half contributes at any given moment to the generation of torque. High magnet costs limit application of the structure to small motors.
The objective of the present invention is, therefore, to advance a permanently excited transverse flux machine in such a manner that a stable design of the machine is achieved at low material and production costs.